Many vehicle seat belt retractors include a vehicle sensitive sensor. The vehicle sensitive sensor is responsive to certain vehicle conditions, such as vehicle deceleration and tilt, for preventing rotation of a spool of the retractor in a belt withdrawal direction.
It is common in some types of vehicles to locate the seat belt retractor in the backrest portion of the seat. When a seat belt retractor that is mounted in the backrest portion of the seat includes a vehicle sensitive sensor, the reclining or folding of the backrest portion of the seat may result in the vehicle sensitive sensor preventing rotation of the spool in a belt withdrawal direction. The spool of the retractor, however, may still rotate in the belt retraction direction to retract seat belt webbing. If the seat belt webbing retracts into the retractor when the backrest portion of the seat is in a folded condition and the vehicle sensitive sensor prevents rotation of the spool in the belt withdrawal direction, the seat belt webbing is prevented from being withdrawn from the retractor. As a result, the seat belt webbing may prevent the backrest portion of the seat from being returned to an upright position.
In some known seat belt systems, a button is sewn onto the seat belt webbing at a predetermined location. When the backrest portion of the seat is in an upright position and the seat belt webbing is fully retracted, the button on the seat belt webbing engages a structure within the retractor for preventing further retraction of the seat belt webbing. When the backrest portion of the seat is folded, no further seat belt webbing may be retracted into the retractor. Since the distance between the retractor and the anchor for the seat belt webbing is shortened when the backrest portion of the seat is folded, a loose portion of the seat belt webbing is formed when the backrest portion of the seat is folded. This loose portion of the seat belt webbing may hang to the side of the seat and is subject to damage from events such as being closed in the vehicle door.
A mechanism for disabling the vehicle sensitive sensor under certain conditions, such as a folded condition of the backrest portion of the seat, is desired. Such a mechanism, however, should not hinder the proper operation of the vehicle sensitive sensor when the seat belt webbing is being used for restraining an occupant in a vehicle seat.
A vehicle seat generally includes a seat back latch mechanism that must be moved to an unlatched condition for enabling the backrest portion of the seat to be folded or reclined relative to the seat cushion. When the seat back latch mechanism is in the latched condition, the backrest portion of the seat is fixed relative to the cushion portion of the seat. When the seat belt retractor is located in the backrest portion of the seat, the seat back latch mechanism must be in the latched condition for the seat belt webbing to help restrain the forward movement of the torso of the occupant of the seat. If the seat back latch mechanism is in the unlatched condition during the occurrence of a vehicle crash event, the backrest portion of the seat will move with the torso of the occupant and the seat belt webbing will not restrain movement of the torso.
It is desirable to prevent an occupant from withdrawing seat belt webbing from the seat belt retractor until the seat back latch mechanism is in the latched condition. By preventing the withdrawal of the seat belt webbing until the seat back latch mechanism is in the latched condition, the occupant will be forced to place the seat back latch mechanism in the latched condition prior to withdrawing and buckling the seat belt webbing. As a result of the seat back latch mechanism being placed in the latched condition to fix the backrest portion of the seat relative to the cushion portion, the seat belt webbing may help to restrain movement of the torso of the occupant.